Length is the easy part: about 2 yards should be enough. Better to trim some excess than to come up short.
As for materials, well, what kind do you want? :-) More seriously, his is probably deerskin leather, which you can buy from various places online. Some fabric stores and local leather retailers may also have similar colored leather. For a belt, any leather belt that looks right to you should work. If your waist size is below average, you can probably find a nicely-worn one cheap at a thrift store. Otherwise, you could cut a long-enough strip of leather (somewhat longer than your waist size, so you have a bit to work with) and either tie it or buckle it yourself.
If I think of more, I'll post more.